After the first discovery of Carbon nanotubes (CNTs) in 1991, there has been a rapid growth in the use of CNTs in various fields such as medical applications, high strength composites, energy devices, electronic applications and the like. Crystallinity of CNTs is a crucial factor for the use of CNTs in various fields. However, the crystallinity of CNTs is difficult to control.
Various processes have been suggested for the synthesis of crystalline CNTs at high temperature with vaporization and decomposition of precursors under a continuous flow of hydrogen. The vaporization and decomposition of precursors is carried out using additional heaters connected to the growth furnace. However, the cost of the CNT-production increases exponentially with rise in the temperature. Further, CNTs with high crystallinity are produced by post-synthesis processes. The post-synthesis processes such as oxidation or hydrothermal treatment comprising separation, purification, dispersion, and the like, are cumbersome as well as non-economical.
Further, the enhancement of crystallinity has been achieved by introducing either water-vapor/oxygen/carbon dioxide gas or sulfur containing compound into the synthesis process. But, that again results in higher production cost of the carbon nanotubes.
Therefore, there still exists a need for providing a cost-effective process for the synthesis of crystalline CNT-films/mats at a lower temperature and without using hydrogen as a carrier gas.